U.S. patent application number 10/506477 was filed with the patent office on 2005-06-09 for fan having an integrated ip protection.
Invention is credited to Weisser, Michael.
Application Number | 20050123423 10/506477 |
Document ID | / |
Family ID | 7968560 |
Filed Date | 2005-06-09 |
United States Patent
Application |
20050123423 |
Kind Code |
A1 |
Weisser, Michael |
June 9, 2005 |
Fan having an integrated ip protection
Abstract
A fan has a fan housing (2) which is formed with a pot-shaped
recess (4) and it has an external-rotor drive motor (103) having an
internal stator (22) and an external rotor (34), separated from
each other by an air gap (52). The internal stator (22) is mounted
on a bearing support tube (24) which is connected to a base part
(46). The arrangement of bearing support tube (24) and base part
(46) form, together with the pot-shaped recess portion (4) of fan
housing (2), a substantially fluid-tight annular space (54)
enclosing the inner stator (22). A wall (56) defining this annular
space (54) extends in the manner of a canned motor through the air
gap (52) between inner stator (22) and external rotor (34).
Inventors: |
Weisser, Michael;
(Furtwangen, DE) |
Correspondence
Address: |
WARE FRESSOLA VAN DER SLUYS &
ADOLPHSON, LLP
BRADFORD GREEN BUILDING 5
755 MAIN STREET, P O BOX 224
MONROE
CT
06468
US
|
Family ID: |
7968560 |
Appl. No.: |
10/506477 |
Filed: |
September 1, 2004 |
PCT Filed: |
February 11, 2003 |
PCT NO: |
PCT/EP03/01312 |
Current U.S.
Class: |
417/423.7 ;
417/357; 417/423.1 |
Current CPC
Class: |
F04D 29/083 20130101;
F04D 25/0646 20130101; H02K 11/33 20160101; H02K 7/14 20130101;
H02K 1/187 20130101; F04D 25/062 20130101; H02K 5/128 20130101 |
Class at
Publication: |
417/423.7 ;
417/423.1; 417/357 |
International
Class: |
F04B 017/00; F04B
035/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 2, 2002 |
DE |
2002 0421.6 |
Claims
1. A fan, comprising: an external-rotor motor (103) having an
internal stator (22) and an external rotor (34) separated therefrom
by an air gap (52); a bearing support tube (24) mounted on a base
(46), the internal stator (22) being mounted on the support tube
(24); and a pot-shaped part (4, 56; 58, 70) having one end
connected to said base (46), forming a substantially fluid-tight
annular space (54) enclosing said internal stator (22), and having
a wall (56; 70) which extends in the manner of a canned motor
through said air gap (52) between the internal stator (22) and the
external rotor (34).
2. The fan of claim 1, wherein an end of said bearing support tube
(24) which is remote from said base (46) extends to a portion (6;
68) of said pot-shaped part (4; 68) and forms a substantially
fluid-tight connection therewith.
3. The fan of claim 1, wherein the base (46) forms a substantially
fluid-tight connection (10') with a fan housing (2).
4. The fan of claim 1, wherein said base (46) is fluid-tightly
connected to the fan housing (2) by ultrasonic welding.
5. The fan of claim 1, wherein said pot-shaped part (4; 56) has a
welding bead (10) for formation of a welded connection.
6. The fan of claim 1, wherein said bearing support tube (24) is
formed with a recess (14) in which a spacer (18), a retaining
element (20) for securing the shaft (40), and a plurality of rotary
bearings (16) are provided.
7. The fan of claim 6, wherein said recess (14) of the bearing
support tube (24) is configured as a blind bore (14).
8. The fan of claim 6, wherein the recess (14) of the bearing
support tube (24) is so configured, at its closed end, that it
radially guides a retaining clip (20) placed therein.
9. The fan of claim 6, wherein the rotor is configured as an
external rotor (34) with a rotor bell (38) onto which a rotor shaft
(40) is secured; between the rotor bell (38) and an inner ring of
one of the rotary bearings (16), a spring (44) is provided, which
is compressible during assembly, to facilitate engagement of a
retaining clip (20) placed in the recess (14) of the bearing
support tube (24) into a circumferential groove (48) formed on the
rotor shaft (40).
10. The fan of claim 9, wherein the retaining clip (20) has at
least one detent hook (21) which, in an assembled state, engages
into the circumferential groove (48) formed on the rotor shaft
(40).
11. The fan of claim 1, wherein the motor is an electronically
commutated motor (103) whose rotor (34) has a rotor magnet (36) and
has a stator (22) with a stator lamination stack (26), the stator
being arranged, at least partially, radially inside the rotor
magnet (36).
12. The fan of claim 11, wherein the rotor (34) is arranged
substantially in magnetic equilibrium relative to stator lamination
stack (26), in order to reduce or avoid any axially directed
magnetic force between rotor (34) and stator (22).
13. The fan of claim 1, wherein the pot-shaped part (6; 56) is
integrally formed with the housing (2) of the fan.
14. The fan of claim 1, wherein the base (46) connected to the
bearing support tube (24) is integrally formed with the housing (2)
of the fan.
15. The fan of claim 1, wherein a fluid-tight connection between
the pot-shaped part (58, 70) and base (46) is achieved by
adhesion.
16. The fan of claim 1, wherein the rotor (34) has a shaft (40)
which is axially fixed by a securing ring (60) which engages into a
circumferential groove of the shaft (40).
17. The fan of claim 1, wherein a fluid-tight connection between
the pot-shaped part (58,70) and base (46) is achieved by
welding.
18. The fan of claim 2, wherein said bearing support tube (24) is
formed with a recess (14) in which a spacer (18), a retaining
element (20) for securing the shaft (40), and a plurality of rotary
bearings (16) are provided.
19. The fan of claim 18, wherein said recess (14) of the bearing
support tube (24) is configured as a blind bore (14).
Description
[0001] This application is a sec. 371 of PCT/EP03/01312, filed 11
Feb. 2003, claiming priority of DE 202 20 421 of 2 Mar. 2002.
FIELD OF THE INVENTION
[0002] The Ingress Protection (IP) standards for electrical
machines are designated with abbreviations, e.g. safety standard
IP23, according to which resistance to sprayed water from
perpendicular or diagonal directions is required, or safety
standard IP44, according to which resistance to splashed water from
all directions is required. The present invention relates to a fan
which is adapted to satisfy higher safety standards.
BACKGROUND
[0003] A fan generally has a fan housing with integrated
reinforcing ribs, a flange with bearings arranged therein, a
securing mechanism for the rotor shaft, and a stator with a circuit
board mounted on an adjacent flange. DE 200 12 673 U1 (assigned to
Papst-Motoren and corresponding to EP 1,076,398) discloses such a
fan, comprising essentially a stator, a lamination stack, a
winding, a stator tube, a circuit board, and a rotor. The rotor
comprises essentially rotor magnets, a rotor bell or cone on which
fan blades are arranged, and a rotor hub.
[0004] In the case of electric motors which are installed in
so-called "clean rooms" or in moist or aggressive environments, it
is necessary to provide the sensitive parts of a motor, e.g. the
winding and circuit board, with a protective layer or barrier, in
order to satisfy high insulation and protection requirements, i.e.
such a fan must have a specified kind of protection, depending upon
its use.
[0005] Thus, it is known, for example from WO 98-19382 and
corresponding U.S. Pat. No. 5,973,424, to coat the stator of a
electric motor with plastic resin. The object of this disclosure is
essentially to provide the connection between stator and circuit
board in simpler form. Methods of creating such a protective
coating, such as dipping, submerging, vacuum-impregnating, vacuum
die-casting, and dripping-in, are known in the prior art.
[0006] Nevertheless, it is recognized that these methods not only
require mechanical post-processing, but also fail to satisfy the
requirements of the higher protection standards.
SUMMARY OF THE INVENTION
[0007] It is an object of the invention, to provide a fan
configuration which facilitates integrated IP protection,
preferably satisfying even the higher insulation and protection
standards.
[0008] According to the invention, this object is achieved by
mounting an internal stator on a bearing support tube, and then
using a pot-shaped part, sealed to a base, to form a fluid-tight
enclosure around the internal stator. Such a fan combines simple
assembly and cost-effective, environmentally-conscious production
with reliable functioning, even under difficult environmental
conditions, and short cycle times are achieved in its
manufacture.
[0009] Further advantages and features of the present invention
will be apparent from the following embodiments described and
illustrated in the drawings.
BRIEF FIGURE DESCRIPTION
[0010] FIG. 1: a plan view of a fan housing of a first embodiment
of the invention, looking along the direction of arrow 1 of FIG.
2;
[0011] FIG. 2: a section along line II-II of FIG. 1;
[0012] FIG. 3: an enlargement of detail III of FIG. 2;
[0013] FIG. 4: a plan view of a flange, looking along direction IV
of FIG. 5;
[0014] FIG. 5: a section along line V-V of FIG. 4;
[0015] FIG. 6: a section through a flange with stator placed
thereon;
[0016] FIG. 7: a section through a complete fan according to the
first embodiment of the invention;
[0017] FIG. 8: an enlargement of detail VIII of FIG. 7;
[0018] FIG. 9: a plan view of a fan housing with a protective
shroud, according to a second embodiment of the invention, along
direction IX of FIG. 10;
[0019] FIG. 10: a section along line X-X of FIG. 9;
[0020] FIG. 11: a plan view of a cover cap, along direction XI
of
[0021] FIG. 12; and
[0022] FIG. 12: a section along line XII-XII of FIG. 11.
DETAILED DESCRIPTION
[0023] FIG. 1 and FIG. 2 illustrate a fan housing of a fan. Fan
housing 2 has, on its rear side, multiple, essentially round
pot-shaped recessed portions 4 with stepped respective diameters,
whose walls are designated 56 (see FIGS. 2 & 3). The
thus-created recessed portions are fixedly connected with the outer
segments of fan housing 2. Additional, optional, reinforcing ribs 8
increase the stiffness of the pot-shaped recessed portions 4 and
guarantee a non-wobbling seating of a stator flange 101 in fan
housing 2 (FIGS. 5 & 6). Inside the deepest pot-shaped recessed
portion 4 there is provided, centrally located, an essentially
round raised portion 6. It serves for positioning and fixation of
stator flange 101, as shown in FIG. 6. Additionally, there is a
welding bead 10 on the outer side of one of the essentially round
recessed portions 4, as shown in FIG. 3. Its purpose is explained
in the following description.
[0024] FIGS. 4 and 5 show a flange 101 in an unassembled state.
Flange 101, essentially round, has multiple annular concentrically
arranged recesses 14, an essentially cylindrical bearing support
tube 24 and a base portion 46. The latter is formed as a round
plate or disc without through-holes, i.e. the recesses 14 are
formed as a blind bore.
[0025] Flange 101 (FIG. 5) is preferably made of plastic, e.g. from
polyamide with 30% glass fiber reinforced plastic, but could,
however, be made of other materials such as aluminum, steel, etc.
Into this flange 101, there is engaged a retaining clip 20, whose
outer form is matched to the form of the recess 14, as shown, and
which is provided, as shown, with detent hooks 21. Then, the ball
bearings 16 and the spacer element 18 are pressed in.
[0026] Thereafter, according to FIG. 6, a stator 22 is shoved onto
the bearing support tube 24, up to a predetermined end position.
The securing of stator 22 into the required end position can be
achieved by gluing or press-fitting. However, other fastening and
fixing methods, such as clipping or using detect hooks, are
possible. The fact that the mounting onto flange 101 of the ball
bearings 16, the spacer element 18, the retaining clip 20, the
stator 22 and subsequently of the rotor 24 all are done from the
same side, namely from above in FIG. 6, offers substantial
advantages in terms of automation.
[0027] The completely component-mounted flange 101 of FIG. 6 is
subsequently slid into the underside of fan housing 2. The
positioning and centering of flange 101 is achieved by means of
raised portion 6 (FIGS. 2 & 3), which is inside the
concentrically arranged pot-shaped recessed portions 4 of FIG. 2.
At this occasion, one of the recesses 14 (FIG. 5) of bearing
support tube 24 engages with raised portion 6 (see FIG. 7).
[0028] FIG. 6 is a section through flange 101 in the
component-mounted state. This flange 101 has, within recess 14, the
two ball bearings 16, the spacer 18, and the retaining clip 20.
Stator 22 is separately placed onto the essentially round bearing
support tube 24. Stator 22 comprises essentially a lamination stack
25, a winding 28, and a circuit board 30. On the circuit board 30
are found electronic components 32 which could be destroyed by
moisture and aggressive media, such as salt-laden air.
[0029] FIG. 7 illustrates, in section, the structure of a fan
according to the first embodiment of the invention. The fan
comprises the fan housing 2, the completely component-mounted
flange 101 with the ball bearings 16, the spacer 18, the retaining
clip 20 and an electronically commutated external rotor motor (ECM)
103 essentially comprising stator 22 and rotor 34. The rotor 34
comprises essentially a rotor magnet 36, a rotor bell 38, a rotor
shaft 40 securely anchored to the rotor bell, and a rotor hub 42.
Rotor 34 is arranged substantially in a state of magnetic
equilibrium relative to stator lamination stack 26, in order to
reduce or minimize magnetic force operating, in an axial direction,
between rotor 34 and stator 22.
[0030] FIG. 8 shows, greatly enlarged, how wall segment 56 of
pot-shaped recessed portion 4 is arranged in air gap 52 in the
manner of a canned motor, and insulates stator 22 from rotor
34.
[0031] The pre-mounted flange 101 is, during assembly, slipped so
far into the underside of fan housing 2, until base portion 46 of
flange 101 abuts the welding bead 10, as shown in FIG. 8.
[0032] Fan housing 2, with inserted flange 46, is subsequently
passed through an ultrasonic welding device. In this, the welding
bead 10 is heated up, and brought to the melting point. Due to the
dead weight of flange 46 or due to supplemental pressure on the
flange, it assumes its final position on the underside of fan
housing 2. After hardening of the melted welding bead 10' (FIG. 8),
the base part 46 of flange 101 is fluid-tightly and securely
connected to the underside of fan housing 2. Flange 101 can also be
secured on the underside of fan housing 2 by gluing, press-fitting,
or other methods. The preferred securing method for flange 101 is a
function of the material used for the fan housing and for the
flange.
[0033] On the opposing face of the housing rear wall of fan housing
2, a compensating spring 44 is installed centrally; see FIG. 7. The
rotor bell 38 with rotor magnet 36 and fixedly anchored rotor shaft
40 is thereafter inserted into the housing. In the process, the
compensating spring 44 is compressed, and the shaft 40 is inserted
so far that the detent hooks 21 of retaining clip 20 engage in a
circumferential groove 48 of the rotor shaft 40. The rotor shaft 40
and the rotor bell 38 connected therewith, and the injection-molded
fan blades 50 are thereby secured axially with respect to stator
22. The compensating spring 44 serves to absorb axial play between
rotor 34 and stator 22, to assist assembly in the manner
illustrated, and for tensioning of the ball bearings 16.
[0034] According to the first embodiment, stator 22, together with
circuit board 30, is enclosed on its upper side (as shown in FIGS.
6 & 7) by pot-shaped element 4, whose wall 56 extends through
the air gap 52 (see FIG. 8) and forms an annular space 54 enclosing
the inner stator 22. Element 4 is, at its open end, fluid-tightly
connected to flange part 46, as shown in FIG. 8. The upper (as
shown in FIGS. 6 & 7) end of bearing support tube 24, whose
lower end is closed, forms a connection with raised portion 6 of
pot-shaped element 4, and the shaft 40 passes through this portion
6. One thereby obtains a cost-effective insulation of the stator of
stator 22 with very good characteristics.
[0035] FIGS. 9 through 12 illustrate a second embodiment of a fan
with integrated IP protection. For parts which are identical to
those of FIG. 1, or identically operative, the same reference
numerals are used. The fan has a fan housing 2 with a molded-on
flange 12; see FIG. 10. This flange 12 comprises essentially a base
part 46 and a bearing support tube 24 formed with one or more
centrally arranged recesses 14. Into the bearing support tube 24,
ball bearings 16 are press-fitted, as shown. Thereafter, the stator
22, complete with the lamination stack 26, the winding 28 and the
circuit board 30 (including electronic components 32) are slid onto
the bearing support tube 24. Stator 22 is slid onto the bearing
support tube 24 until it reaches a specific predetermined end
position. In this end position, stator 22 is secured to the bearing
support tube by press-fitting, gluing or other securing means.
[0036] Subsequently, a cover cap 58 (FIGS. 11 & 12), which is
essentially round, is reverse-drawn over the stator 22. After its
mounting over stator 22, cover cap 58 rests on base part 46 of
flange 12 (see FIG. 10) and is secured in this end position to fan
housing 2, e.g. by adhesion. Thereby, cover cap 58 forms, together
with fan housing 2, a fluid-tight enclosure. Subsequently, a
compensating spring 44 is installed, centrally with respect to the
fan housing rear wall. A rotor bell 38, with rotor magnet 36 and
fixedly anchored rotor shaft 40, are then introduced into the
housing. In the process, compensating spring 44 is compressed, and
the shaft 40 is brought so far into bearing support tube 24 that a
circumferential groove 48 of the rotor shaft 40 becomes visible on
the rear side of fan housing 2. Then a securing ring 60 is engaged
into the circumferential groove 48 of rotor shaft 40. Thereby,
rotor shaft 40, and the rotor bell 38 having molded-on fan blades
50, are secured axially with respect to stator 22. The compensating
spring 44 serves to absorb axial play between rotor 34 and stator
22 and biases the ball bearings 16 relative to each other. After
the assembly, the opening of bearing support tube 24 is closed off
in the manner shown, e.g. by a type or model plate.
[0037] FIGS. 11 & 12 illustrate the open-ended cover cap 58.
This has one or more centrally aligned, essentially round,
pot-shaped recesses 62. In addition, there is a central
through-hole 68, formed with a collar, which enables the rotor
shaft 40, after the assembly of the fan, to pass through the
housing. The free end of bearing support tube 24 projects into this
collar of through-hole 68, as shown in FIG. 10, forming a seal
therewith. A cylindrical segment 70 of cover cap 58 extends, in the
manner of a canned motor, through the air gap 52 of the motor; see
FIG. 10.
[0038] An advantage of the invention is that, with this
arrangement, one can manufacture cost-effectively in an
environmentally responsible manner. There are enormous savings in
materials and time, and short cycle times on the production line.
Further, in the manufacture of the stators, and the associated
necessary Ingress Protection (IP), no polyurethane potting
compounds or associated tools are needed. Defects such as
blowholes, fissures, and voids, which occur with the conventional
methods, are avoided. Subsequent time-consuming reworking is thus
also avoided. Further, this method is well adapted for mass
production, since it can be quickly and efficiently adapted for
making varied models.
[0039] The invention is not limited to the embodiments shown and
described, but rather encompasses all similarly operating
variations and modifications.
* * * * *